Electric switch and light fixture



Feb. 24, 1942. T. J. MUDON 2,274,377

ELECTRIC SWITCH AND LIGHT FIXTURE Filed May 12, 1941 4 Sheets-Sheet 1 I1121; 1''. $.21} l 1 E 4? I Z! I I, I l i 47 1 25 I, Q \j r 1 fizz/67222?" i .T/ianzaa J/lfuciaz'a Feb. 24, 1942.

T. J. MUDON ELECTRIC SWITCH AND, LIGHT FIXTURE Filed May 12, 1941 4Sheets-Sheet 2 I Feb. 24, 1942. T. J. MUDON 2,274,377

ELECTRIC SWITCH AND LIGHT FIXTURE Filed May 12, 1941 4 Sheets-Sheet 3 90W 104 40 1041"" J1 i five7z7 fonzcas J/Yudon Feb. 24, 1942. T. J. MUDON2, 7 77 ELECTRIC SWITCH AND LIGHT FIXTURE Filed May 12, 1941 v 4Sheets-Sheet 4 1/2 I if? E fill/6722. 07

Patented Feb. 24, 1942 ELECTRIC SWITCH AND LIGHT FIXTURE Thomas J.Mudon, Chicago, Ill., assignor to Safe Delay Switch Corporation,Chicago, 111., a corporation of Illinois Application May 12, 1941,Serial No. 393,097

(01. zoo-+33) 14 Claims.

The present invention relates to time delay control mechanisms andcomprises an improvement upon the time delay control mechanism coveredby my previous Patent No. 2,202,297 of May 28, 1940. In the patent thereis disclosed a time delay control mechanism whereby the time lag isaccomplished by moving a creeping element along a track.

It is the principal purpose of the present invention to provide animproved time delay control mechanism comprising a creeping element anda track together with means for varying the pressure between thecreeping element and track in response to changes in temperature. I havediscovered that the rate of creeping of the creeping element in thiscombination is peculiarly responsive to changes in temperature. Whenwarmed up the rate of creeping speeds up and when cooled the rate ofcreeping is slower. This is particularly true where the creeping elementis made of rubber, either of the natural or synthetic type. Thischaracteristic of change in creeping speed due to relatively remotechanges in temperature (which characteristic 1 term nerve lag") results.in a suflicient variation in the rate of creeping to prevent a seriousproblem in the accurate timing of the delay accomplished by the use ofthe creeping element and track.

Specifically I have found that by using, in the supporting means for thecreeping element and track, a temperature responsive member such as abimetallic strip I am able to compensate for the change in nerve lag ofthe creeping element. I thus can maintain a time lag setting constantover a sufficiently wide range of temperatures for all practicaloperations.

In its simplest form the new combination comprises a creeping element ofrubber, either natural or synthetic, and a track element comprising abimetallic bar. Pressure is applied through the mounting of thebimetallic bar which is at some distance from the point of engagement ofthe track and the creeping element. The bar is so mounted that as thesurrounding atmosphere warms up and the temperature of the creepingelement therefore increases the bar moves the part of the track engagedby the creeping element toward the creeping element thus to increase thepressure between the track and the element to offer greater resistanceto the creeping action. When the surrounding atmosphere cools thetemperature of the creeping element decreases but at the same time thebar moves the track away from the creeping element so as to decrease thepressure between them and make it easier for the element to creep alongth track.

My invention is not confined however to such a simple combination as thetemperature compensating means may be of any other suitable form capableof causing separation of the creeping element and track as thetemperature decreases or causing them to approach each other as thetemperature increases. It is immaterial to the present invention in itsbroader aspects whether the track or the creeping element be stationary.It is only essential that they be pressed against each other and that adefinite force be provided to move one with respect to the other.

In the several forms of the invention shown herein, the features ofwhich comprise specific features of novelty, spring means is used toprovide the definite force by which the movement of the creeping elementalong the track is caused. Also, means are provided whereby the periodof delay may be carried by the simple expedient of varying the pressureof the creeping element upon the track.

The preferred form of my invention is illustrated in and comprises atime delay control switch mechanism for connecting a source of currentsuch as a battery to a small lamp in a unit which is adapted to serve asa source of illumination in closets and other small dark areas whereillumination by the usual lamp has not been provided. It will beappreciated that a portable unit of this type, self-contained in itsentirety, finds a multitude of applications in existing structures. Ithas the advantage that constant drain upon the power source is avoidedbecause the time delay control mechanism automatically disconnects thepower source from the lamp after a predetermined time and yet the unitremains ready at any time to furnish light in the dark area where it issituated.

Other and more specific objects and advantages of the invention willappear as the description proceeds, reference being had to theaccompanying drawings wherein a preferred form of the invention and anumber of mechanical modifications thereof are illustrated. It is to beunderstood however that the drawings and description are illustrativeonly and should not be taken as limiting the invention beyond the scopeto which it is justly entitled in view of the prior art and inaccordance with the appended claims.

In the drawings:

Fig. 1 is a view in front elevation of a lighting device embodying thepresent invention;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a sectional view taken on the line 33 of Fig. 1;

Fig. 4 is an enlarged fragmentary view illustrating the relativepositions of the creeping element and track as the creeping element ismoved toward its operative position with respect to the track;

Fig. 5 is a view similar to Fig. 4 illustrating the relative positionsof the creeping element and track during the time delay period;

Fig. 6 is a sectional view through the creeping element and its mountingtaken on the line 68 of Fig. 5;

Fig. 7 is a sectional View taken on the line '|'l of Fig. 8 illustratinga modified form of the invention;

Fig. 8 is a view taken on the line 8-8 of Fig. 7;

Fig. 9 is a view taken on the line 99 of Fig. 8;

Fig. 10 is a view similar to Fig. 8 but showing the parts in changedposition where the time delay mechanism is being set to begin its opera-Fig. 11 is a view like Fig. 10 showing the mechanism during the timedelay operation;

Fig. 12 is a view in side elevation of another modification of theinvention;

Fig. 13 is a sectional view taken on the line |3|3 of Fig. 12;

Fig. 14 is a view like 12 showing a change in position of the parts;

Fig. 15 is a fragmentary sectional view taken on the line |5|5 of Fig.14;

Fig. 16 is a view in side elevation of a further modification;

Fig. 17 is a sectional view taken on the line il|l of Fig. 16;

Fig. 18 is a view in side elevation looking at the device shown in Fig.16 from the back side as indicated by the line |8|8 of Fig. 17;

Fig. 1.9 is a view similar to Fig. 18 illustrating the parts in changedposition;

Fig. 20 is a view in side elevation of a further modification; and

Fig. 21 is a fragmentary sectional view taken on the line 2|'-2| of Fig.20.

Referring now in detail to the drawings,the present invention isillustrated as a time delay control mechanism whereby a lamp 22 may be oilluminated for a snort time'on a source of current comprising suitabledry cells 23, 24 and automatically turned oiT. The lamp' and dry cellsare mounted in a casing 25 which comprises a back plate 25 and a shell21 having a front portion 28 that is translucent. Preferably the frontportion 28 comprisesa sheetof transparent or translucent plasticmaterial such for example as the material sold under the trade nameLucite. The shell 2'! ispreferably of metal and the back plate 25 is ofinsulating material; for example, a synthetic resin compound such asthat sold under the trade name Bakelite. A mounting clip 29 is fastenedat the top of the casing 25 so that the entire device may be hung on anail or other simple mounting means. Within the casing 25 I providesuitable holding spring brackets 3 and 3| upon which the dry cells 23and 24 rest. I also provide side supports 32 and and top clips 34 and 35for engaging the dry cells. The several elements just described arefastened to the back plate 26 by screws. The top clips 34 and 35 .areconnected together by a cross bar 35 so that they may serve with thecross bar as a conductor for connecting the two dry cells in series. Thespring bracket 3| forms part of a plate 3'! that extends upwardly alongthe back plate 26 and then toward the center of the back plate where itis offset at 38 to provide a lamp mounting 33 for the lamp 22. A screwsocket 40 is provided on the portion 39 to receive the screw threadedbase of the lamp 22. The opposite terminal of the lamp at the center tipis engaged by a spring contact 4| which is mounted upon a frame 42 forthe time delay control mechanism. The frame 42 is fastened to the backplate by suitable screws and the mounting of the spring contact 4| issuch as to insulate it from the frame 42. The frame 42 is howeverdirectly connected to the supporting spring brackets 33 by a contactstrip 43.

The time delay control mechanism is carried entirely by the frame 42.The spring contact 44 is electrically connected to the contact spring 4|and extends downwardly inside the frame 42 as shown in Figs. 1 to 3,inclusive, the free end of this spring contact being bent outwardly asshown in Fig. 1. The frame 42 supports a spring plate 45 which isriveted at 45 to the frame and which is bent into substantially L-shape. Two ears 4'! and 48 are turned up on the plate 45 near its freeend. These ears support a pivot pin 49 which serves as a pivot for twoarms 50 and 5| that carry a creeping element 52 of rubber which isfirmly fixed toa supporting bar 53. The ends 54 and 55 of the supportingbar 53' are rectangular in cross section and are slidably mounted indiagonal slots 56 and 51 in the arms 50 and 5|. The end portions 54 and55 are urged toward one end of their respective slots by springs 58 and59 which are mounted on th arms 50 and 5|. It will be noted from anexamination of Fig. 6 that the creeping element 52 is directly moldedonto a roughened portion 53a of the bar 53. This is to insure adhesionof the creeping element to the bar and to prevent any possibility of thecreeping element becoming rotatable upon the bar.

The creeping element is urged from the dotted line position indicated inFig. 2 toward the full line position by a spring 50 which is coiledaround the pin 49. One end ill of the spring presses against the plate45 and the other end 62 extends lengthwise of the arm 5| and is securedthereto. The arm 50 serves as a contact element for engagement with thespring contact 44. When the creeping element is in the full lineposition shown in Fig. 2 the spring contact 44 does not engage the arm50 and the circuit for the lamp 22 is open. However, when the creepingelement is in the dotted line position shown in Fig. 2 the springcontact 44 is in engagement with the arm 50 and therefore the circuitfor the lamp 22 is closed.

A track element 53 is fixed upon a flange 54 of the frame 42 so as toextend downwardly into the path of movement of the creeping element 52.The track element 53 is slotted and is held in place by a screw thatthreads into the flange 64. It is thus possible to initially adjust theposition of the track element 63. The track element 63 has its creepingelement engaging portion 55 oifset as shown best in Figs. 2, 4

.and 5 and has an extension 66 extending at tion, the pressure beingcontrolled by an adjustthese figures the time delay mechanism is meingscrew 61 which is threaded in a boss 68 on the frame 42 and whichengages under a curved portion 69 at the free end of the plate 45. Itwill be evident from an inspection of Fig. 2 that by moving the screw 61inward or outward the creeping element will be pressed toward or awayfrom the track element. If more pressure is applied between the twoelements the rate at which the creeping element will traverse the trackelement is slower. Also, if the temperature of the creeping elementdrops the rate at which the element creeps with respect to the trackbecomes slower. In order to compensate for the changes in creeping ratedue to temperature changes I so mount the track element as to cause itto recede from the creeping element upon a drop in temperature and toapproach the creeping element upon a rise in temperature. This isaccomplished by making the track element 63 of a bimetallic,thermostatic material wherein one strip of metal 63a has a differentrate of expansion than the other strip of metal 63b in response totemperature changes. The strip 631; has the greater response totemperature changes so that upon cooling it contracts faster than thestrip 63a, thus tending to curve the combined strip in acounterclockwise direction about its point of support as illustrated inFigs. 2 and 4.

In order to move the creeping element into operative position I providea pull chain 18 which is fastened to the arm supporting the creepingelement. This pull chain passes through an opening 1| in the bottom ofthe shell 21. The opening 1| has a reduced portion at 12 into which thepull chain may be hooked when it is desired to maintain the lamp 22lighted for a period of time longer than the time delay provided by thecreeping element and track. If it is desired at any time to break thecircuit of the lamp 22 without waiting for the creeping element tocomplete its travel across the track the operator can press a plunger 13upwardly against the angularly extending portion 86 of the track to thusmove the track away from the creeping element enough to release thecreeping element instantaneously. The plunger 13 is carried in the shell21 and is prevented from dropping out by a pin 14.

The frame 42 is provided with means to limit the downward movement ofthe creeping element. This means comprises an offset extension 15 whichextends into the way of the arm 5|.

In the operation when it is desired to close the circuit for the lamp 22the creeping element is moved down by a pull on the chain 10. As thecreeping element passes downwardly over the track portion 65 it ispermitted to back up because the rectangular end portions 54 and of thebar 53 can slide along the slots in the arms 58 and 5| against thepressure of the springs 58 and 59. It therefore requires very littlepressure to move the creeping element past the track portion. Thisavoids excessive wear on the creeping element and makes the mechanismeasier to operate. However, when the movement of the creeping element isin an upward direction as illustrated in Fig. 5 the rectangular portions54 and 55 have moved out under the influence of the springs 58 and 59 tothe other ends of the slots 55 and 51 so that the full pressurecontemplated in the setting of the screw 81 is now exerted between thecreeping element and the track.

Referring now to Figs. '1 to 11, inclusive, in

chanically of a slightly different construction although there is nochange in the creeping element and its mounting or in the track elementand its mounting.

To avoid confusion the same reference numerals are applied to the sameparts wherever these parts have not been essentially changed. In thisform of the invention the frame 42 is provided with two ears 16 and 11in which a pin 18 is journaled to provide a pivotal support for the arms58 and 5| that carry the creeping element 52. In this form of theinvention there is a pin 19 passing between the two arms 50 and 5|adjacent to the creeping element 52. A coil spring 88 is wound about thepin 18, one end 8| of the spring bearing against the pin 19 and theother end 82 thereof being bent around a reduced end portion 83 upon anadjusting screw 84 that is threaded in the fram 42. By turning the screw84 the tension of the spring 8| may be increased or decreased to thusgovern the force tending to make the creeping element 52 traverse thetrack element 63. The operating mechanism in this form of the inventioncomprises a lever 85 which is pivoted on the end of the pin 18 outsideof the arm 5|. A spring 86 is coiled around the pin 18 outside of thelever 85 and normally tends to move the lever 85 into its inoperativeposition, that is, the position shown in Fig. 8. The pin 19 extendsthrough the arm 5| and provides a post 81 which is adapted to cooperatewith a spring latch 88 that is mounted on the frame 42. The spring latch88 is offset at 89 intermediate its ends and has its free end portion 90slightly diverging outwardly. The lever 85 is offset at 9| to extendinwardly across the arm 5| and is then bent at substantially rightangles as shown at 92 in Fig. 7 so as to extend through a slot 93 in theframe 42. The free end of the extension 92 has a pull chain 94 thereon.

The operation of the device is as follows:

Assuming that it is desired to move the creeping element from theposition shown in Fig. 8 to the position shown in Fig. 10, which wouldbe the normal circuit closing position, the lever 85 is moved by meansof the pull chain 94. Its offset portion 9| engages the arm 5| and movesthe creeping element with it to the position shown in Fig. 10. Thespring latch 88 engages over the post 81 and locks the creeping elementin the position shown in Fig. 10.

The contact elements for the switch mechanism have been left off themodifications since they are no different than those employed in themain form of the invention. It will be evident however that when theparts are in the position shown in Fig. 10 contact would be establishedbetween the arm 50 and the spring contact 44. This contact will bemaintained as long as the latch 88 is permitted to engage over the post81. However when the operator desires to put the time delay mechanism towork by bringing the creeping element 52 into contact with the track 63he again operates the lever 85 which in the meantime has returned to itsoriginal position under the force of the spring 86. This time uponoperation the lever 85 engages under the spring latch 88 because thefree end is turned out by the pull exerted on the spring latch by thepost 81. The spring latch is thus lifted off of the post 81 asillustrated in Fig. 11 and the creeping element is permitted to comeinto contact with the track element. The time delay action then takesplace the same as in the main form of the invention. .With .this deviceit is therefore possible to close a circuit foras long a time as isdesired and then by another operationof the switch lever to throw thetime delay mechanism .into operation so that the circuit will thereafterremain closed only for thepredetermined time that it takes for thecreeping element to pass across the track. This mechanism isparticularly useful in suchplaces as coal bins, fruit cellars and thelike where at many times it desirable to have a light on for asubstantial period of time; yet it is desirable also to be able to getout of the dark space before the light goes out.

Referring now to the modification illustrated in Figs. 12 to 15,inclusive, in this modification all of the electrical connections havebeen left off for the sake of clearness.

The frame 42 and the mounting of the arms 50 and I, together with thecreeping element 52 and the track element 63, are identical with themodification just previously described. In this form of the inventionhowever the setting of the time delay mechanism is accomplished by asliding bar 95. The bar 95 is slidably mounted in the opposite sides ofthe frame 42. The bar is notched as indicated at 95 with a relativelydeep notch having a long sloping surface 91. The bar is further notchedat 98 with a small notch in the form of a broad V. A latch element 99 isfixed to the frame 42 at I00 and extends parallel with the direction ofmovement of the bar 95 past the arm 50 which carries the creepingelement 52. In this form of the invention there is a post IOI projectingfrom the arm 50 and the latch 99 has an aperture I02 into which the postextends. The free end I03 of the latch 99 is offset toward the bar 95and overlaps it as shown in Fig. 14. This free end is formed into abroad V-shape to match the notch 98. On the side opposite the notches 96and 98 the bar 95 is cut out as illustrated at I04 (see Figs. 13 and15).

The operation of this form of device is as follows:

Assuming that the operator desires to set the time delay switchmechanism to work he would normally find the parts in the'positionillustrated in Fig. 12. In this position the spring latch 99 would beresting in the notch 98 and the time delay creeping element would befree of the track. By pressing down upon the bar 95 to move the bar fromthe position shown in Fig. 12 to that shown in Fig. 14 the operatorcauses the notch I04 to move the arm 50 down to the position shown inFig. 14. At the same time the downward movement of the bar 95 causes theend I03 of the spring latch 99 to move into the notch 96. This permitsthe post IOI to move into the aperture I02 and lock the arm 50 in theposition shown in Fig. 14. This is the circuit closing position inaccordance with the first form of the invention. Now when it is desiredto set the time delay mechanism into operation the bar 95 is returned toits original position. This causes the spring latch 99 to be lifted sothat the post IOI is released from the aperture I02 and the creepingelement 52 is allowed to engage the track -33. The time delay actionthen takes place in the same fashion as in the main form of theinvention.

Referring now to the form of device illustrated in Figs. 16 to 19,inclusive, in this form of device, as before, the frame 42, the creepingelement 52' and the track 63 are constructed the same as in themodification illustrated in Figs. 7 to 11, inclusive. In this form oftheinvention however the operating mechanism by which the creepingelement is moved to operating position comprises a shaft I05 (see Fig.17) having a knob I06 thereon, the shaft being journaled in two suitableears I01 and I00 provided on the frame 42. This shaft has fixed theretoa cam arm I09 which lies just outside the ear I01 on the frame 42. Thiscam arm I09 has a free end portion IIO which extends inwardly beyond thearm 5I so that when the shaft I05 is turned from the position shown inFig. 16 to the position shown in Fig. 19 the extension IIO engages withthe arm 50 and moves the creeping element from the position shown inFig. 16 to the position shown in Fig. 19. A spring I I I is wound aboutthe shaft I05 and is under tension tending to turn the shaft to theposition where the cam arm I09 is held out of contact with the arm 50.The friction of the portion I I0 on the arm 50 is however sufiicient tohold the shaft I05 against turning when the parts are in the positionshown in Fi 19.

In this form of the invention I have illustrated a simple contactmechanism that provides a novel combination with the time delaymechanism. This contact mechanism comprises two stationary springcontacts H2 and H3 which are mounted upon but insulated from the frame42. The plate II4 of insulating material is pivoted upon the supportingpin 18 which also supports the arms 50 and 5I. This plate carries aspring contact I I5. The pin I9 has an extension I I6 which extendsoutside the arm 5|. The plate H4 has a large round aperture II'I intowhich the extension H5 extends. When the creeping element 52 is releasedfrom the track 63 the springs cause it to advance rapidly and theextension IIS therefore snaps against the wall of the aperture II'I soas to quickly break the contact between the movable contact element H5and the stationary contact element II2.

Referring now to Figs. 20 and 21, in this modification a very simplemechanism is provided whereby to adjust the pressure between thecreeping element 52 and the track 53. In this form of the invention theframe 42 has formed thereon a curved, notched bar I20. The creepingelement 52 is carried by suitable arms 50 and 5|, the arm 50 in thisinstance being provided with an offset portion I2I to which a pull chainI22 is attached. A spring plate I23 is fastened to the frame 42 and hascars like the ears in Figs. 1 to 3, inclusive, supporting a pivot pinI24 on which the arms 50 and 5I are secured. A spring I25 is mountedabout the pin I24 and has one and bearing on the plate I23 and the otherend fixed to the arm 50 so as to tend to move the creeping element intothe position shown in Fig. 1.

In order to adjust the pressure of the creeping element upon the track Iprovide a wire I26, one end 521' of which extends through an apertureI28 in the corner of the frame 42 and the other end of which extendspast the notched bar I20 so that it rides in the notches in the bar.This wire has an offset portion I29 behind the plate 23, the offsetportion being adapted to move the if end of the plate I23 out away fromthe base or the frame 42 more or less depending upon which notch in thebar I20 the end portion I30 02' the wire happens to engage. I find thatthis mechanism gives me an unusually wide range of adjustment for thepressure between the creep- .ing element. Furthermore, it isparticularly usefui for getting very fine adjustments and it isinexpensive to manufacture.

From the foregoing description it is believed that the construction andoperation of the device embodying my invention will be clear to thoseskilled in this art. Having thus described my invention what I claim asnew and desire to secure by Letters Patent is:

1. Time delay control mechanism of the character described comprising amovable member, means for urging said member in one direction, arelatively stationary member, one of said members having a yieldablecreeping element and the other member having a track along which thecreeping element must travel, the creeping element being compressed byengagement with said track whereby to oppose the force of said urgingmeans, one of said members including a temperature responsive device forvarying the pressure of the creeping element upon the track.

2. A time delay control mechanism of the character described, a springpressed actuating member, and a relatively stationary member forretarding movement of said actuating member, said members havingcooperating elements engaging each other yieldingly under pressure tooppose movement of said actuating member, and temperature responsivemeans to vary the pressure between said elements in response totemperature changes.

3. A time delay mechanism comprising a creeping element of resilientmaterial, the hardness of which changes in response to changes in thetemperature thereof, a track along which said element creeps, meansurging said element along the track, supporting means for said elementand the track and temperature responsive means forming part of saidsupporting means arranged to vary the spacing of the element and trackto compensate for the change in hardness of the creeping element.

4. A time delay mechanism comprising a creeping element of resilientmaterial, the hardness of which changes in response to changes in thetemperature thereof, a track along which said element creeps, and asupport for said track comprising a bimetallic strip operable toincrease the spacing of the creeping element and track as the creepingelement hardens.

5. Time delay control mechanism of the character described comprising amovable member, means for urging said member in one direction, arelatively stationary member, one of said members having a yieldablecreeping element and the other member having a track along which thecreeping element must travel, the creeping element being compressed byengagement with said track whereby to oppose the force of said urgingmeans, and a temperature responsive device cperably associated with saidelements and urging means to oppose changes in the rate of creeping ofthe creeping element along the track element due to temperature changesof the elements.

6. Time delay control mechanism of the character described comprising amovable member, means for urging said member in one direction, arelatively stationary member. one of said members having a yieldablecreeping element and the other member having a track along which thecreeping element must travel, the creeping element being compressed byengagement with said track whereby to oppose the force of said urgingmeans, and a temperature responsive device operably associated with saidelements and urging means to oppose changes in the rate of creeping ofthe creeping element along the track element due to temperature changesof the elements, said temperature responsive means comprising abimetallic strip carrying one of said elements.

7. A time delay mechanism comprising a creeping element, a trackelement, one movable along the surface of the other in response to forceapplied thereto, said elements being positioned to press against eachother during their creeping movement and temperature responsive means0perably connected to said elements to oppose change in the rate ofcreeping of one element along the other due to changes in thetemperature of the elements.

8. A time delay mechanism comprising a creeping element, a trackelement, one movable along the surface of the other in response to forceapplied thereto, said elements being positioned to press against eachother during their creeping movement and temperature responsive meansoperably connected to said elements to oppose change in the rate ofcreeping of one element along the other due to changes in thetemperature of the elements, said temperature responsive meanscomprising a bimetallic strip carrying one of said elements.

9. A time delay mechanism comprising a creeping element, a trackelement, one movable along the surface of the other in response to forceapplied thereto, said elements being positioned to press against eachother during their creeping movement and temperature responsive meansoperably connected to said elements to oppose change in the rate ofcreeping of one element along the other due to changes in thetemperature of the elements, said temperature responsive meanscomprising a bimetallic strip and said track element comprising aportion of said strip.

10. A timedelay mechanism comprising a bimetallic strip, a portion ofsaid strip being bent with respect to the remainder thereof to provide atrack, a creeping element, a lever arm carrying said element, andyieldable means for moving said lever arm to force the creeping elementalong the track.

11. A time delay mechanism comprising a bimetallic strip, a portion ofsaid strip being bent with respect to the remainder thereof to provide atrack, a creeping element, a lever arm carryng said element, andyieldable means for moving said lever arm to force the creeping elementalong the track, said creeping element comprising a roughened metal coreand a covering of rubber.

12. A time delay mechanism comprising a bimetallic strip, a portion ofsaid strip being bent with respect to the remainder thereof to provide atrack, a creeping element, a lever arm carrying said element, andyieldable means for moving said lever arm to force the creeping elementalong the track, said creeping element being movably mounted on thelever for limited movement in a direction diagonal to its path ofmovement across the track whereby when crossing the track in onedirection the element may recede from the track but when crossing thetrack in the opposite direction the element may not recede from thetrack.

13. A time delay mechanism comprising a bimetallic strip, a portion ofsaid strip being bent with respect to the remainder thereof to provide atrack, a creeping element, a lever arm carrying said element, andyieldable means for moving said lever arm to force the creeping elementalong the track, said lever arm being mounted for movement toward andaway from the track, and means to adjust the lever toward and away fromthe track.

14. A time delay mechanism comprising a bimetallic strip, a portion ofsaid strip being bent with respect to the remainder thereof to provide atrack, a creeping element, a lever arm

